This vector data set contains the rock unit polygons for the surficial geology in the Delaware Coastal Plain covered by DGS Geologic Map Series No. 20 (Millsboro and Whaleysville Quadrangles). The geological history of the surficial units of the Millsboro Quadrangle and Delaware portion of the Whaleysville Quadrangle was the result of deposition of the Beaverdam Formation during the late Pliocene and its subsequent modification by erosion and deposition related to sea-level fluctuations during the Pleistocene and late Pleistocene upland swamp and bog deposition. The geology at the land surface was then further modified by periglacial activity that produced dune deposits and Carolina Bays in the map area. Surficial geologic mapping was conducted using field maps at a scale of 1:12,000 with 2 foot contours. Stratigraphic boundaries drawn at topographic breaks reflect detailed mapping using contours not shown on this map. An additional dataset of datapoints used to generate rock unit polygons for the surficial geology in the Delaware Coastal Plain covered by DGS Geologic Map Series No. 20 (Millsboro and Whaleysville Quadrangles) exists for use in conjunction with this dataset.
This data is accessible as a map service on Delaware FirstMap.
Additionally, this and other services are available in the ArcGIS Online DGS Map Viewer
+/- 1 foot. Drill holes and hand auger holes have been averaged together to get this value.
+/- 20 feet. Boring sites are located on topographic base maps and aerial photography. Spot checking of these locations using GPS has verified this accuracy.
University of Delaware
Delaware Geological Survey Building
Newark, DE 19716
Mon - Fri; 8:00am to 4:30pm